<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <mate http-eauiv="X-UA-Compatible"content="IE=edge"></mate>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
     <script src="vue.js"></script>
</head>
<body>
    <div id="app">
        {{msg}}
    </div>
    <script>
        var vm = new Vue({
        el: '#app',
        data: {
        msg: "ok"
        },
        beforeMount() {
            console.log('挂载之前')
            console. log(this.Sel.innerHTML) //通过this Sel 获取el的DOM元素
        },
        mounted(){
            console.log('挂载之后')
            console.log(this.Sel.innerHTML)
        }
    })
        </script>
</body>
</html>